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RE: faceted classification

From: Aida Slavic <aida@acorweb.net>
Date: Tue, 23 Mar 2004 11:20:33 -0000
To: <public-esw-thes@w3.org>
Message-ID: <AAEKLFPLCPPCFCOACDKICEDFCKAA.aida@acorweb.net>

Alistair,
couple of things related to the article in question and XFML and
Sense1/Sense2
in case this may be relevant for SKOS

> I just read the article [1] that Doug forwarded.  I was wondering if you
> could help to me to clear something up.

This is a library school essay and for me it was very useful as it
clearly demonstrated how easy it is to ignore the difference between
classification of objects and classification of
knowledge - which is a typical for American library schools.
But it is very important to pay attention to this as it represents
how the term 'faceted classification'
is implemented in XFML and how it is understood by many people creating
business portals with excellent browsing facets functionality.

In this approach "faceted classification" is classification that is
fits in your Sense 1 (division according to one principle at the time,
hence "faceted classification" is ANY classification that operates
with sets of mutually exclusive categories of any kind). Here everything
fits
nicely as term 'facet' (fr. la facette - little face) is said to be borrowed
from a 'diamond' - each facet represents one side or one face of the
diamond.
(each property is a single face of a multifaced object). With this one gets
all the advantages in managing vocabulary using an elegant relational model.
If one knows that most widely used American classifications such as Dewey or
Library of Congress C. are enumerative classifications and
occasionally/often? fail to
consistently apply a simpliest logic of division - then it is understandable
why many feel necessary to make distinction between: a) messy enumerative
structure
b)pure taxonomy and c) something called "faceted classification" simply to
emphasise that the last one is a logical and consistent in nature and in the
same
time helps in managing different properties of objects simultaniously
(and is likely to be ontologically clean in Guarino's sense and therefore
easier to process by machines). Something like 'deux ex machina' on the KOS
scene.

UK Classification research group, however, reserves the expression
'faceted classification' for knowledge classification only (knowledge about
objects
and not objects themselves). Here one obviously has more problems to sort
out
with facets than detergents, beer cans and bottles of wines. For CRG Sense1
is
understood to be there anyway and when they attach attribute 'faceted' to
some
classification they think that besides this basic logical property level
there
must be a set of fundamental categories (Sense 2) in place.
When thesauri embraced 'facet analysis' they paid attention only to the
top organizational structure in a Sense2 and ignored Sense1. The reason
being the very nature
of thesaurus: alphabetical indexing languages do not need detailed
classificatory structure for
their managment and can work with a rather rough organizational grouping as
far as
there is some logical principle behind it (mutual exclusiveness).

The discussion on what faceted classification is on the
facetedclassification
mailing list last year agreed on the following (I think):
a)  if one is creating a classification
for objects/entities (bottles of wines, beer cans, detergents, cars etc.)
than it is sufficient to have Sense 1 organization structure applied.

b) if one is producing classification to classify knowledge about objects
both: facets of properties and fundametnal facets above them in order to be
able
to organize facets themselves. This is because of the complexity that
classification of
knowledge operates with, dealing with concepts as well as dynamic
relationships among them.

The conclusion was that XFML is not meant and can't serve for the purpose b)
and suggestion was
that we should rather look into XTM in order to accommodate the kind of
ontology typical for
 "faceted classifications of knowledge" which operate with fundamental
categories (Sense 2: grouping of primitives)
as well as with facets in a more technical sense (Sense1: things according
to their properties).

If we would code Sense 2 only - does this mean that we would undermine the
following???
a) the need for knowledge classification to deal with Sense1 and Sense2
b) the understanding and implementation of faceted principle in a Sense 1 in
classification of objects
(as in XFML)
c) the underlying classificatory nature of thesaurus that can be potentially
fully coded
and may provide better support in vocabulary control and use
(thesaurofacet/classaurus)
d)

Aida



>
> I have so far come across two meanings for 'faceted classification':
>
> (Sense 1)
>
> A set of things are 'classified' according to their properties.
> For example
> (from [1]) a set of detergents are classified by 'brand name', 'form',
> 'scent', 'agent', 'effect on agent' and 'special property'.  In
> this sense,
> each of these properties represents a 'facet' through which the set of
> instances can be viewed.
>
> (Sense 2)
>
> A set of 'concepts' are grouped according to their most primitive
> type.  For
> example, the concept 'marble' is placed in the 'materials' facet.  The
> concept 'insects' is placed in the 'organisms' facet.  In this sense, a
> 'facet' is essentially a primitive class, and every member of a
> facet group
> is either an instance or a sub-class of that class.
>
> So my first question is: have I described these two senses
> accurately (or am
> I missing something)?
>
> My second question is: are there any other senses of 'faceted
> classification' worth considering?
>
> Finally: if my analysis is correct, these two senses describe quite
> different systems of organisation (*).  So would it be useful in the short
> term to come up with unambiguous names for these two meanings?
> For example,
> we could refer to sense 1 as 'classification by description' and
> sense 2 as
> 'primitive classification'.
>
> Please let me know what you think.
>
> Yours,
>
> Alistair.
>
>
> (*) although sense 2 could be viewed as a special case of sense
> 1, in which
> concepts are classified according to the value of a 'primitive type'
> property - i.e. 'primitive type' represents a 'facet' in sense 1!
>
> [1] <http://www.miskatonic.org/library/facet-web-howto.html>
>
> ---
> Alistair Miles
> Research Associate
> CCLRC - Rutherford Appleton Laboratory
> Building R1 Room 1.60
> Fermi Avenue
> Chilton
> Didcot
> Oxfordshire OX11 0QX
> United Kingdom
> Email:        a.j.miles@rl.ac.uk
> Tel: +44 (0)1235 445440
>
>
>
>
Received on Tuesday, 23 March 2004 06:12:30 GMT

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